In recent years, a charge control device which controls charging of a battery mounted on a vehicle using a solar cell (sunlight energy) has been proposed positively. For instance, in a controller of an electric vehicle disclosed in the following patent document 1 (PTL1), an electric power generated by a sunlight panel installed outside is supplied to an auxiliary battery which supplies an electric power to electrical apparatus inside the vehicle. And, this conventional controller boosts the electric power of an auxiliary battery and charges a main battery which supplies an electric power to a motor when the remaining capacity of the auxiliary battery reaches a predetermined value.